1. Technical Field
This application related to a structure of ACLED, especially related to a vertical stack ACLED structure.
2. Description of the Related Art
The light-emitting diodes (LEDs) of the solid-state lighting elements have the characteristics of low power consumption, low heat generation, long operational life, shockproof, small volume, quick response and good opto-electrical property like light emission with a stable wavelength, so the LEDs have been widely used in household appliances, indicator light of instruments, and opto-electrical products, etc. As the opto-electrical technology develops, the solid-state lighting elements have great progress in the light efficiency, operation life and the brightness, and LEDs are expected to become the main stream of the lighting devices in the near future.
Generally speaking, the conventional LED is driven by direct current (DC). An AC-DC inverter is required to invert DC to AC. Since the inverter has large volume and heavy weight, the cost is added and the power is loss during inverting. Therefore, it is difficult for LED to compete with the existing light source mainly because of the price concern.
The ACLED can solve the problems mentioned above. It can decrease the volume and weight of LED, extend to more applications, decrease the cost in inverter element, and decrease the 15˜30% power loss of conventional DC-AC in inverting so the light efficiency of the whole LED is increased.
Nevertheless, the ACLEDs normally keep the growth substrate such as sapphire to form an anti-parallel connection structure in horizontal orientation, so the size is as twice as that of the conventional single chip. Accordingly, the space and cost is wasted.